Ok, I have read many posts and articles on this and other forums about the 550 relaying mail to whatever.com is not allowed issue. It seems to come and go with my server setup. My clients are a bit testy about it these days... which makes my blood pressure go up . I want to get you good folks to relook at the following data and see if you can concur my thoughts... or suggest other options to correct the situation. I will try to be as specific as I can without making you crazy. > I have a RH9, Plesk 7.5.3, VPS, with about 70 domains on it. > I have my primary domain which is also signified in the Plesk server setup as the server "full host name" on one IP address. I have the rest of the domains set to share another IP address. > The DNS template sets NS1 & NS2 for all of the domains as the same ones used by my primary domain and NS1 is used to share the domains. > Thus, IP xx.xxx.xxx.20 is the server's and my primary domain's mail host... and IP xx.xxx.xxx.25 shows up as the shared domain's mail host. Here is what DNSReport. shows as a WARNING. WARNING: One or more of your mailservers is claiming to be a host other than what it really is (the SMTP greeting should be a 3-digit code, followed by a space or a dash, then the host name). This probably won't cause any harm, but is a technical violation of RFC821 4.3 (and RFC2821 4.3.1). Note that the hostname given in the SMTP greeting should have an A record pointing back to the same server. mail.shareddomain.com claims to be host primarydomain.net [but that host is at xx.xxx.xxx.20, not xx.xxx.xxx.25]. With all of that said, could this be the reason that I am getting the "550 relaying" error? Gosh, I hope all of that made sense. If this is an issue, is there a way to correct it without changing a lot of the DNS stuff? Thanks for your time and wisdom!